Microstructural Study of YBCO Thin Films With Stripe-Patterned Substrates for Ultra-Fine Multi-Filaments

Rare-earth barium copper oxide (REBCO) superconductors can be applied to superconducting magnets in low-temperature and high-magnetic-field and electric power equipment. Currently available superconducting wires supplied by many companies are tape-shaped, and a thin REBCO film is formed by depositing multiple buffer layers on a thin metal substrate. Coated conductors fabricated on such a flat substrate have a structure close to a single crystal and have high critical current density properties. In contrast, reducing the screening current is an important issue for practical applications such as high-field superconducting coils. In this study, we proposed a patterned multifilamentary thin film with a stripe pattern, fabricated on a substrate via photolithography. YBa₂Cu₃O_x was deposited onto stripe with Nb metal. Any stripe material can be used to separate superconducting and non-superconducting wires based on magneto-optical observations. Based on TEM/STEM-EDX observations, impurity phases such as NbBaO were formed on the STO/Nb strip. These results suggested that the use of a substrate with a stripe pattern is useful for fabricating multifilamentary coated conductors.